Network monitoring in Developer Tools doen't work

Hello,
Just a quick question - is network monitoring for add-ons working? I remember I was using this a while ago but now I cannot see any requests there. It works fine for normal pages but when I’m debugging my background page, I just don’t see any requests there - only the “Reload” button that will (wrongly) reload my add-on.

I just tested it on Beta and Developer Edition on Windows and it just won’t work.
And it seems to work on Ubuntu using Release version.

Can somebody confirm this please? Thank you!

EDIT:
after reproducing it in my second Windows PC in Firefox 58, 59 and 60 I reported it:
https://bugzilla.mozilla.org/show_bug.cgi?id=1435959